The present invention relates to a new and improved wall system or curtain wall and more particularly to vertical members or mullions employed therein. A unitary thermal barrier of a fail-safe construction is provided.
In the construction of modern day multi-story buildings, a variety of wall systems or curtain wall structures have been utilized. U.S. Pat. Nos. 3,719,014 and 3,858,375 are illustrative of these types of construction.
Generally these curtain walls are constructed of metal framing members with extruded aluminum members being preferred for many installations. The various components of the wall system are factory fabricated and transported to the job site. Vertical and horizontal members are constructed in predetermined shapes and lengths. These members are assembled piece by piece into a grid directly on a building. The grid is then glazed from either the inside or outside of the building depending upon job conditions. Spandrel panels or other types of panels may be installed along with the metal members if desirable
A number of wall systems employ various types of thermal grid barriers or thermal breaks in the grid or frame members as well as a thermal break between the panel members and the grid or frame members to prevent heat transfer from one member to the other. Present methods require the use of thru bolts, approximately 10 to 12 inch centers isolated with rigid plastic to provide structural strength for the thermal break. Such procedure necessitates a great amount of labor for fabrication and assembly in the plant or on the job site as well as added material costs. After installation of the curtain walls or wall system, there is always the risk that the barrier material will lose its structural integrity, either partially or wholly, because of uncontrollable influences such as elevated temperatures caused by a fire inside or adjacent to the wall system. When structural integrity is lost, it is likely that glass or other panels comprising the wall system will fall from the building.
It is therefore a primary object of the present invention to provide an improved curtain or wall system for buildings which provides for a fail-safe condition whereby complete separtion of metal members is prohibited.
Another object of the invention is to provide a novel wall system wherein the various components thereof may be quickly and easily installed from the inside of the building without the necessity of employing thru bolts or similar fastening devices.
Still another object of the instant invention is to provided an improved unitary thermal break vertical mullion or frame member for curtain walls or wall systems which is completely fabricated at a plant or shop thereby eliminating the expense and risk entailed with job site assembly.
Another important object of the present invention is to prevent a short circuit of the thermal break wherein horizontal mullions or framing members are isolated from vertical mullions by the use of suitable hard thermal materials attached to appropriate locations on the vertical mullions or to the ends of the horizontal mullions.
Other objects and advantages of the invention will become more readily apparent from a consideration of the following description and drawings.